Please note, this page is printable by selecting the normal print options on your computer.
Why count carbohydrate?
Carbohydrate counting can make it easier to control your diabetes and improve your HbA1c. Modern insulins mean we are able to be much more precise in deciding on the right doses of short
acting insulin needed through the day. If you can work out how much carbohydrate there is in the meal you are about to eat, you can decide how much short acting insulin you will need. It can also
be helpful for those who want to lose weight. By reducing the amount of carbohydrate eaten and reducing the amount of insulin needed, you can avoid unnecessary weight gain.
What is carbohydrate?
Carbohydrate is the term used for any food which becomes sugar in the blood, once it has been digested; this includes both starches and sugars. Sugars include glucose, sucrose, lactose, fructose, dextrose and maltose.
What foods are counted?
All types of bread, chapatti, naan
Cereals – e.g. porridge, bran flakes
Grains – e.g. rice, wheat,
Pasta and couscous.
Potato, yam, sweet potato.
Crisps and savoury biscuits.
Fruit – fresh, dried, juice, tinned
Biscuits and cereal bars.
Cakes, pastry and pastries.
Most thick soups and sauces.
Chocolate, sweets, honey.
Sugar and sugary drinks.
Beer, cider and liqueurs.
Plain meat, fish and poultry
Eggs, cheese and butter
Vegetables and salads
Pulses and beans
Nuts and seeds
Wine and spirits
Stock and seasonings – salt, pepper
Tea and coffee
Fats and oils
Herbs and spices
Sweeteners – Aspartame (Candarel), sucralose
(Splenda), saccharin, and stevia.
Not all foods that are free from carbohydrate should be eaten freely:
• Fats and oils contain large amounts of calories and should be used sparingly.
• Too much salt could increase your blood pressure.
How does ‘carb counting’ work?
There are some simple steps to learning how to ‘carb count’. These are:
1. Understand which foods do and do not contain carbohydrate.
2. Work out how much carbohydrate is in the meals and snacks you are eating.
3. Work out your ‘ratio’ – how much carbohydrate will be covered by 1 unit of insulin.
4. Use your ‘correction’ – correct any high or low blood glucose.
5. Keep a record of your blood glucose and insulin and spend some time thinking about whether or not the insulin you have taken was right for the CHO you ate.
How do I know how much carbohydrate is in my food?
Your dietitian can give you a list of the carbohydrate values of some common foods. These values are shown as the amount in a normal sized portion. Food labels will give the carbohydrate values of the product. Look for ‘total carbohydrate’ not just the ‘of which sugars’. The carbohydrate amount is usually per 100g or per serving. Be aware that the size of your serving may be different from the packet serving size. There are some good sources of information available, including:
o ‘Carbs & Cals’ Book or app, Cheyette & Balolia
o ‘Carbs Count e-book’ Diabetes UK
Most people start on a ratio of 1unit of insulin to 10g of carbohydrate. This can then be adjusted according to your blood glucose. Some people may need as much as 1 unit of insulin to 5g carbohydrate or less, some may need as little as 1unit of insulin to 20g carbohydrate. You can find out your ratio by keeping your carbohydrate, blood glucose and insulin diary. Blood glucose dropping after a meal can indicate that you have not counted your carbohydrate properly, so recheck. It can also indicate that your ratio is too high and needs to be reduced (e.g. if your ratio is 1unit to 10g carbohydrate change it to 1unit to 15g carbohydrate and continue to record your blood glucose to see if this has worked).
If your blood glucose increases after a meal you may have underestimated the carbohydrate in your meal or your ratio is too low and needs to be increased (e.g. if your ratio is 1 unit to 10g carbohydrate change it to 1 unit to 5g carbohydrate and continue to record your blood glucose).
Checking background insulin
It is important to remember when using your ratio that it will only be accurate if your long acting or background insulin is correct. If background insulin is too little your blood glucose will creep up gradually throughout the day, if too much it will drop throughout the day.
You can check if your background insulin is correct by eating a carbohydrate free meal as follows:
1. Take your background insulin as normal.
2. Do not eat any carbohydrate or take your fast-acting insulin for this meal.
3. Check your blood glucose once or twice before your next meal.
This way the background insulin will not have the influence of carbohydrate or fast acting insulin and you can assess whether your dose is correct.
You can make corrections to your blood glucose throughout the day rather than leaving a high or low blood glucose to continue. A correction is usually done at mealtimes.
Most people find that 1u of insulin will decrease/increase blood glucose by 2-3 mmol/l. It is useful to start with this calculation and adjust as you find out more. Some people may have a correction
of 1u insulin 4mmol/l and others 1unit insulin to 1mmol/l. For example, you have a ratio of 1 unit to 10g carbohydrate and a correction of 1 unit to 3mmol/l and your blood glucose before your meal is 14mmol/l. Your meal contains 70g of carbohydrate, so you know you need 7 units of quick acting insulin for the meal. You may wish to reduce your blood glucose and make a ‘correction’ here so you would need to take an extra 2 units of quick acting insulin with your meal to reduce your blood glucose by 6 mmol/l from 14mmol/l to 8mmol/l. So, you would take 9 units in total for the meal. Likewise, if your blood glucose was 4 mmol/l before the meal, you might wish to reduce your mealtime dose of insulin by 1 unit to bring your blood glucose up by 3 mmol from 4mmol/l to 7 mmol/l. So, you would take 6 units for the meal. Recording in your carbohydrate, blood glucose and insulin diary will help you work out what your correction is.
Working out the ‘carbs’ in home cooking
• Look at the recipe and decide which ingredients contain carbohydrate.
• Calculate the carbohydrate content of each ingredient.
• Add them all together and divide the total by the number of portions.
• You could also use an app like ‘Cook and count’ which contains the carbohydrate content of thousands of ingredients and calculates.
• You can look up the nutrition information of the food in many restaurants online. Choose your meal and work out the carbohydrates beforehand. Some restaurants have standard menus and may be able to tell you the carbohydrate content of the food.
• Carbohydrate counting apps give the carbohydrate content with pictures of commonly eaten foods – it is quite easy to check and estimate the size of the portion.
• If you are eating take-away food, you can weigh it at home and use a carbohydrate counting book to find the most similar food.
• Learn by experience. If your guess was not quite right the first time, make a note and then you will be more accurate if you choose that dish again.
• Get used to what average portions of foods look like on your plate, and then you will be more able to guess accurately, if eating out.
• Make a list of the carbohydrate values of the foods you eat most often.
• Learn to judge the carbohydrate content of your favourite foods by using the same bowl or plate.
• Every so often, weigh your foods to check your memory.